Die offset die to die bonding

ABSTRACT

A semiconductor die is provided on a spacer, the die having first and second opposite edges which extend beyond respective first and second opposite edges of the spacer, the first edge of the die extending beyond the first edge of the spacer to a lesser extent than the second edge of the die extends beyond the second edge of the spacer. Furthermore, a first semiconductor die has a plurality of bond pads thereon, a second semiconductor die has a plurality of bond pads thereon, and a substrate has a plurality of bond pads thereon. Each of a first plurality of wires connects a bond pad on the first semiconductor die with a bond pad on the second semiconductor die, and each of a second plurality of wires connects a bond pad on the second semiconductor die with a bond pad on the substrate.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to semiconductor devices which includea plurality of stacked semiconductor die, and more particularly, toconstructing such a device with improved performance and yield.

2. Background Art

FIG. 1 illustrates a multi-die semiconductor device 40 (shown insimplified form), with the die in stacked relation. As shown in FIG. 1,a carrier substrate 42 has a chip attach surface 44. A semiconductorchip or die 46 is attached to the surface 44 of the substrate 42 by adie bond. A spacer 48 is attached to the die in stacked relation by adie bond, and a semiconductor die 50 is attached to the spacer 48 instacked relation by a die bond. A semiconductor die 52 is attached tothe die 50 in stacked relation by a die bond. Using standard wirebonding techniques, wires 53, 54, 55 connect bond pads 56, 58, 60 on therespective die 46, 50, 52 with bond pads 62 on the substrate 42.

As will be seen in FIG. 1, the spacer 48 is of smaller dimensions, i.e.,smaller length and width, than the die 46 and the die 50, and the spacer48 is centered on the die 46 therebelow and with relation to the die 50thereon (see FIG. 2). This provides access to the bond pads 56 on thedie 46 for wire bonding of the die 46 to the substrate 42. This alsoresults in the die 50 on the spacer 48 overhanging the spacer 48 asshown. With the die 50 being relatively large (for high deviceperformance), the overhang indicated as of dimension A can be relativelylarge. Connection of the wires 54 to the bond pads 58 on the die 50involves a relative large impact (downward, FIG. 1) by the bonding headon the die 50 on that overhanging portion, which can cause theoverhanging portion of the die 50 to bounce and vibrate. It will be seenthat a large dimension A (resulting in turn in a large lever armdimension B) as shown in FIG. 1 can result in a relatively large bounce,as the lever arm on which force is applied at the bond pads 58 on thedie 50 is relatively large. This excessive bounce can result inimperfect wire bonding, in turn resulting in reduced yield ofmanufactured devices.

FIG. 3 illustrates another multi-die semiconductor device 60 (againshown in simplified form), with the die in stacked relation. As shown inFIG. 3, a carrier substrate 62 has a chip attach surface 64. Asemiconductor chip or die 66 is attached to the surface 64 of thesubstrate 62 by a die bond. A semiconductor die 68 is attached to thedie 66 in stacked relation by a die bond. Using standard wire bondingtechniques, wires 70, 72 connect bond pads 74, 76 on the respective die66, 68 with bond pads 78 on the substrate 62.

FIG. 4 is a plan view of the device of FIG. 3. As shown, the pluralityof wires 70 connect the bond pads 74 on the die 66 with bond pads 78 onthe substrate 62, the other plurality of wires 72 connect bond pads 76on the die 68 with bond pads 78 on the substrate 62. Due to thecomplexity of the device, including the large number of bond pads on thedie and substrate (much greater than the number illustrated), wirecrossings occur (FIG. 4), resulting in increased likelihood of shortingand consequently failure of the device.

Therefore, what is needed is an approach wherein device yield isimproved by reducing the bounce and shorting problems described above.

DISCLOSURE OF THE INVENTION

Broadly stated, the present electronic device comprises a body, and asemiconductor die on the body and having first and second opposite edgeswhich extend beyond respective first and second opposite edges of thebody, the first edge of the die extending beyond the first edge of thebody to a lesser extent than the second edge of the die extends beyondthe second edge of the body.

Broadly stated, the present electronic device comprises a firstsemiconductor die having a plurality of bond pads thereon, a secondsemiconductor die having a plurality of bond pads thereon, a substratehaving a plurality of bond pads thereon, a first plurality of wires,each connecting a bond pad on the first semiconductor die with a bondpad on the second semiconductor die, and a second plurality of wires,each connecting a bond pad on the second semiconductor die with a bondpad on the substrate.

The present invention is better understood upon consideration of thedetailed description below, in conjunction with the accompanyingdrawings. As will become readily apparent to those skilled in the artfrom the following description, there are shown and describedembodiments of this invention simply by way of the illustration of thebest mode to carry out the invention. As will be realized, the inventionis capable of other embodiments and its several details are capable ofmodifications and various obvious aspects, all without departing fromthe scope of the invention. Accordingly, the drawings and detaileddescription will be regarded as illustrative in nature and not asrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well assaid preferred mode of use, and further objects and advantages thereof,will best be understood by reference to the following detaileddescription of illustrative embodiments when read in conjunction withthe accompanying drawings, wherein:

FIG. 1 illustrates an electronic device in accordance with the priorart;

FIG. 2 is a plan view of a portion of the device of FIG. 1;

FIG. 3 illustrate another electronic device in accordance with the priorart;

FIG. 4 is a plan view of the device of FIG. 3;

FIGS. 5 and 6 illustrate embodiments of the invention;

FIGS. 7-11 illustrate further embodiments of the invention; and

FIGS. 12-14 illustrate systems incorporating the present devices.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Reference is now made in detail to specific embodiments of the presentinvention which illustrate the best mode presently contemplated by theinventors for practicing the invention.

FIG. 5 illustrates a multi-die semiconductor device 140 (shown insimplified form), with the die in stacked relation. As shown in FIG. 1,a carrier substrate 142 has a chip attach surface 144. A semiconductorchip or die 146 is attached to the surface 144 of the substrate 142 by adie bond. A body 148 in the form of a spacer is attached to the die 146in stacked relation by a die bond, and a semiconductor die 150 isattached to the spacer 148 in stacked relation by a die bond. The spacer148 is thus positioned between the die 146 and the die 150. Asemiconductor die 152 is attached to the die 150 in stacked relation bya die bond. The relative sizes of these elements are as in FIGS. 1 and2. Again, the spacer 148 is of smaller dimensions than the die 146 andthe die 150, with the edges of the die 150 extending beyond therespective adjacent edges of the spacer 148.

However, instead of being centered on the die 146 therebeneath and withrelation to the die thereon 150, the spacer 148 is positioned in arightward offset (arrow, FIG. 5) relative to the die 146, 150 ascompared to the prior art approach so that the edge 150A of the die 150extends beyond the respective adjacent edge 148A of the spacer 148 to alesser extent (dimension C) than the opposite edge 150B of the die 150extends beyond the respective adjacent edge 148B of the spacer 148. Thisbrings the edge 148A of the spacer 148 closer to the edge 150A of thedie 150, and with the bond pads 158 being mounted on the die 150adjacent that edge 150A and on a surface of the die 150 opposite thesurface thereof adjacent the spacer 148, the lever arm (dimension D)through which force is applied by the bonding head during wire bondingis reduced, decreasing bounce and vibration of the overhanging portionof the die 150 relative to the spacer 148.

The device 140 is completed by providing wires 153, 154, 155 connectingbond pads 156 on the die 146, bond pads 158 on the die 150, and bondpads 160 on the die 152 with bond pads 162 on the substrate 142 by meansof conventional wire bonding. The reduced bounce described above resultsin improved wire bonding by providing less likelihood of faulty bonding,in turn resulting in improved yield of manufactured devices.

FIG. 6 illustrates a multi-die semiconductor device 140 (shown insimplified form), with the die in stacked relation. Similar to thedevice of FIG. 5, a carrier substrate 142 has a chip attach surface 144.A semiconductor chip or die 146 is attached to the surface 144 of thesubstrate 142. A body 148 in the form of a spacer is attached to the die146 in stacked relation by a die bond, and a semiconductor die 150 isattached to the spacer 148 in stacked relation by a die bond. The spacer148 is thus positioned between the die 146 and the die 150. Asemiconductor die 152 is attached to the die 150 in stacked relation bya die bond. The relative sizes of these elements are as in FIGS. 1 and2. Again, the spacer 148 is of smaller dimensions than the die 146 andthe die 150, with the edges of the die 150 extending beyond therespective adjacent edges of the spacer 148.

In this embodiment, instead of being centered on the spacer 148therebeneath, the die 150 (with the die 152 thereon) is positioned in aleftward offset (arrow, FIG. 6) relative to the spacer 148 as comparedto the prior art approach so that the edge 150A of the die 150 extendsbeyond the respective adjacent edge 148A of the spacer 148 to a lesserextent than the opposite edge 150B of the die 150 extends beyond therespective adjacent edge 148B of the spacer 148. This again brings theedge 148A of the spacer 148 closer to the edge 150A of the die 150, andwith the bond pads 158 being mounted on the die 150 adjacent that edge150A and on a surface of the die 150 opposite the surface thereofadjacent the spacer 148, the lever arm (dimension F) through which forceis applied by the bonding head during wire bonding is reduced,decreasing bounce and vibration of the overhanging portion of the die150 relative to the spacer 148.

The device is again completed by providing wire connecting bond pads 156on the die 146, bond pads 158 on the die 150, and bond pads 160 on thedie 152 with bond pads 162 on the substrate 142 by means of conventionalwire bonding. The reduced bounce described above results in improvedwire bonding by providing less likelihood of faulty bonding, in turnresulting in improved yield of manufactured devices.

FIGS. 7-11 illustrate an approach for overcoming the problems set forthabove with regard to FIGS. 3 and 4. FIG. 7 illustrates a multi-diesemiconductor device 340 (shown in simplified form), with the die instacked relation. As shown in FIGS. 8 and 11, a carrier substrate 342has a plurality of bond pads 344 on its upper surface adjacent an edgethereof. A semiconductor chip or die 346 is attached to the substrate342 by a die bond. This die 346 also has a plurality of bond pads 348 onits upper surface, adjacent the bond pads 344 on the substrate 342. Asemiconductor die 350 is attached to the die 346 in stacked relation bya die bond. This die 350 also has a plurality of bond pads 352 on itsupper surface, adjacent the bond pads 348 on the die 346 and the bondpads 344 on the substrate 342.

As shown in FIGS. 7 and 11, wire bonding is undertaken to provide wires354 which connect bond pads 352 on the die 350 with bond pads 348 on thedie 346, i.e., die-to-die connection or wire bonding. Forward wirebonding is undertaken to form these wires 354, i.e., the wires 354 areapplied in the direction from the bond pads 352 on the die 350 towardthe bond pads 348 on the die 346 (see arrow, FIG. 7). Next (FIG. 8),wire bonding is undertaken to provide wires 356 which connect bond pads348 on the die 346 with bond pads 344 on the substrate 342. Forward wirebonding is undertaken to form these wires 356, i.e., the wires 356 areapplied in the direction from the bond pads 348 on the substrate 346toward the bond pads 344 on the die 342 (see arrow, FIG. 8). The wires354, 356 are connected in the manner shown in FIG. 11, wherein each ofthe wires 354 connected to the bond pads 352 on the die 350 areconnected to bond pads 348 on the die 346, with these wires 354 being inseries with wires 356 that connect bond pads 348 on the die 346 withbond pads 344 on the substrate 342. This is to be contrasted with theprior approach wherein bond pads 76 on the die 68 are directly connectedto bond pads 78 on the substrate 62. This approach provides forplacement of wires as shown in FIG. 11, avoiding wire crossing whichwould increase likelihood of shorting and consequent failure of thedevice.

FIGS. 9 and 10 illustrate another approach for achieving the result ofFIG. 11. In this approach, wire bonding between bond pads 348 on the die346 and bond pads 344 on the substrate 342 is undertaken first (FIG. 9),in a reverse direction, i.e., in a direction from the bond pads 344 onthe substrate 342 toward the bond pads 348 on the die 346 (see arrow,FIG. 9). Then, wire bonding is undertaken between the bond pads 352 onthe die 350 and bond pads 348 on the die 346 (FIG. 10), also in thereverse direction from the bond pads 348 on the die 346 toward the bondpads 352 on the die 350 (arrow, FIG. 10. Again, the result of FIG. 11and is achieved.

Device yield is improved by reducing the bounce and shorting problemsdescribed above.

FIG. 12 illustrates a system 400 utilizing devices as described above.As shown therein, the system 400 includes hand-held devices 402 in theform of cell phones, which communicate through an intermediate apparatussuch as a tower 404 (shown) and/or a satellite. Signals are providedfrom one cell phone to the other through the tower 404. Such a cellphone with advantage uses devices of the type described above. Oneskilled in the art will readily understand the advantage of using suchdevices in other hand-held devices 402 such as portable media players,personal digital assistants, digital cameras and the like.

FIG. 13 illustrates another system 500 utilizing devices as describedabove. The system 500 includes a vehicle 502 having an engine 504controlled by an electronic control unit 506. The electronic controlunit 506 with advantage uses devices of the type described above.

FIG. 14 illustrates yet another system 600 utilizing devices asdescribed above. This system 600 is a computer 602 which includes aninput in the form of a keyboard, and a microprocessor for receivingsignals from the keyboard through an interface. The microprocessor alsocommunicates with a CDROM drive, a hard drive, and a floppy drivethrough interfaces. Output from the microprocessor is provided to amonitor through an interface. Also connected to and communicating withthe microprocessor is memory which may take the form of ROM, RAM, flashand/or other forms of memory. The computer with advantage uses devicesof the type described above.

The foregoing description of embodiments of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Other modifications or variations are possible in light ofthe above teachings.

The embodiments were chosen and described to provide the bestillustration of the principles of the invention and its practicalapplication to thereby enable one of ordinary skill of the art toutilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the invention asdetermined by the appended claims when interpreted in accordance withthe breadth to which they are fairly, legally and equitably entitled.

7. An electronic device comprising: a first semiconductor die having a plurality of bond pads thereon; a second semiconductor die having a plurality of bond pads thereon; a substrate having a plurality of bond pads thereon; a first plurality of wires, each connecting a bond pad on the first semiconductor die with a bond pad on the second semiconductor die; and a second plurality of wires, each connecting a bond pad on the second semiconductor die with a bond pad on the substrate.
 8. The electronic device of claim 7 wherein individual wires of the first plurality thereof are connected in series with individual wires of the second plurality thereof through respective bond pads on the second semiconductor die.
 9. The electronic device of claim 8 wherein the second semiconductor die is on the substrate, and the first semiconductor die is in the second semiconductor die.
 17. The device of claim 7 and further comprising said device incorporated in a system.
 18. The device of claim 17 wherein the system is selected from the group consisting of a hand-held device, a vehicle, and a computer. 